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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Installed Sound/Contracting => Topic started by: David Haulman on October 06, 2014, 07:09:57 pm

Title: testing 70 volt speakers
Post by: David Haulman on October 06, 2014, 07:09:57 pm
This customer got a building with some ceiling mounted speakers in it. They appear to be 70 volt. Can I take a small amp with 70 volt output; hook up the speakers and put a tone thru the amp just to see if they all work? no gonna drive it hard. just wanna check them.Any thoughts?
Title: Re: testing 70 volt speakers
Post by: John Roberts {JR} on October 06, 2014, 07:27:59 pm
Yes.. they may not get very loud but you can confirm they do not have rubs or open VC,

JR
Title: Re: testing 70 volt speakers
Post by: Ivan Beaver on October 06, 2014, 07:33:31 pm
This customer got a building with some ceiling mounted speakers in it. They appear to be 70 volt. Can I take a small amp with 70 volt output; hook up the speakers and put a tone thru the amp just to see if they all work? no gonna drive it hard. just wanna check them.Any thoughts?
You could use a normal amp to do that test.  The level may be lower than what you would normally expect from the amp-due to the higher impedance.

So by your statement-I assume there is no amp in place.

To me the FIRST thing I would do would be to do an impedance SWEEP-NOT a DC resistance reading.

This way you can get an idea of what the total load presented to the amplifier would be-assuming the speakers are all properly tapped.

That is the only way you have to get an idea of what size amp you should use.
Title: Re: testing 70 volt speakers
Post by: David Haulman on October 11, 2014, 04:53:00 pm
You could use a normal amp to do that test.  The level may be lower than what you would normally expect from the amp-due to the higher impedance.

So by your statement-I assume there is no amp in place.

To me the FIRST thing I would do would be to do an impedance SWEEP-NOT a DC resistance reading.

This way you can get an idea of what the total load presented to the amplifier would be-assuming the speakers are all properly tapped.

That is the only way you have to get an idea of what size amp you should use.
Yeah. I see. No amp at location. I checked a few of them when I had the lift. I think it will work. Thanks for your Help!